Connection

Abstract

A drill string includes a plurality of tubular members each having a connection with a pin connector and a box connector on adjacent tubular members. The pin connector has an external thread with negative load flanks and positive stab flanks, adapted for threadingly engaging an internal thread second threads with negative load flanks and positive stab flanks on the box connector of the adjacent tubular member. The positive stab flanks have corner radiuses and the negative load flanks have radiuses forming a S-shape. The pin connector has an outer groove for receiving a protuberance on the terminal end of the box member forming locking shoulders. The protuberance and groove have contoured surfaces providing large metal-to-metal contact for preventing the contoured surfaces from sliding during over-torquing and cyclic bending of the drill string. The negative load flanks and locking shoulders lock the connection together. The negative load flanks absorbing the tension and the locking shoulders absorbing the compression on the connection.

1. A method of making up a tubular connection, comprising:
 stabbing a threaded pin member into a threaded box member, said pin member including pin threads and said box member having box threads, said pin threads having stab flanks and load flanks and said box threads having stab flanks and load flanks; 
 engaging corner radiuses on the stab flanks of the pin threads and the box threads; 
 forming a clearance between said threads; 
 rotating the pin and box members relative to each other; 
 guiding said threads on the pin and box members within accommodating grooves on the corresponding pin and box member; 
 engaging contours radiused surfaces on an end of the box member and a base of the pin member; 
 shifting load from the stab flanks to the load flanks on the threads of the pin member and the box member; and 
 locking up the radiused surfaces the radiused surfaces fully contacting each other along the contours. 
 
   
   
     2. The method of  claim 1  further including centering the pin member within the box member. 
   
   
     3. The method of  claim 1  further including stabbing the pin member at least halfway into the box member before the corner radiuses engage. 
   
   
     4. The method of  claim 1  further including engaging the stab flanks and not engaging the load flanks as the threads are guided into the grooves. 
   
   
     5. The method of  claim 1  wherein the engagement of said radiused surfaces causes the load to shift from the stab flanks to the load flanks. 
   
   
     6. The method of  claim 1  further including forming a locking shoulder between the pin base and box end. 
   
   
     7. The method of  claim 1 , wherein said box member has a box base and said pin member has a pin end, said method further including engaging the pin end and box base to form a locking shoulder. 
   
   
     8. The method of  claim 1  further including engaging the pin end and box base to form a locking shoulder prior to said shifting load from the stab flanks to the load flanks. 
   
   
     9. A method of making up a tubular connection, comprising:
 stabbing a threaded pin member into a threaded box member, said pin member including pin threads and said box member including box threads, said pin threads having stab flanks and load flanks and said box threads having stab flanks and load flanks; 
 engaging corner radiuses on the stab flanks of the pin threads and the box threads; 
 forming a clearance between said threads; 
 rotating the pin and box members relative to each other; 
 guiding said threads on the pin and box member within accommodating grooves on the corresponding pin and box members; 
 engaging contours radiused surfaces on an end of the pin member and a base of the box member; 
 shifting load from the stab flanks to the load flanks on the threads; and 
 locking up the radiused surfaces the radiused surfaces fully contacting each other along the contours. 
 
   
   
     10. The method of  claim 9  further including centering the pin member within the box member. 
   
   
     11. The method of  claim 9  further including stabbing the pin member at least halfway into the box member before the corner radiuses engage. 
   
   
     12. The method of  claim 9  further including engaging the stab flanks and not engaging the load flanks as the threads are guided into the grooves. 
   
   
     13. The method of  claim 9  wherein the engagement of said radiused surfaces causes the load to shift from the stab flanks to the load flanks. 
   
   
     14. The method of  claim 9 , wherein said box member has a box end and said pin member has a pin base, said method further including forming a locking shoulder between the pin base and box end. 
   
   
     15. The method of  claim 9  further including engaging the pin end and box base to form a locking shoulder. 
   
   
     16. The method of  claim 9  further including engaging the pin end and box base to form a locking shoulder prior to said shifting load from the stab flanks to the load flanks. 
   
   
     17. A method of making up a tubular connection, comprising:
 stabbing a threaded pin member into a threaded box member, said pin member including pin threads and said box member having box threads, said pin threads having stab flanks and load flanks and said box threads having stab flanks and load flanks; 
 engaging corner radiuses on the stab flanks of the pin threads and the box threads; 
 forming a clearance between said threads; 
 rotating the pin and box members relative to each other; 
 guiding said threads on the pin and box members within accommodating grooves on the corresponding pin and box member; 
 engaging contours radiused surfaces on an end of the box member and a base of the pin member; 
 engaging radiused surfaces on an end of the pin member and a base of the box member; 
 shifting load from the stab flanks to the load flanks on the threads of the pin member and box member; and 
 locking up the radiused surfaces the radiused surfaces fully contacting each other along the contours. 
 
   
   
     18. The method of  claim 17 , wherein said box member has a box end and box base and said pin member has a pin end and pin base, said method further including engaging the pin end and box base to form a first non-sliding locking shoulder, said method further including engaging the box end and pin base to form a second non-sliding locking shoulder. 
   
   
     19. The method of  claim 17  wherein the engagement of said radiused surfaces causes the load to shift from the stab flanks to the load flanks. 
   
   
     20. The method of  claim 17  further including engaging the pin end and box base to form a first non-sliding locking shoulder, and engaging the box end and pin base to form a second non-sliding locking shoulder, prior to said shifting load from the stab flanks to the load flanks.